1. Prepare the Sauce:

In a small bowl, whisk together oyster sauce, soy sauce, dark soy sauce, sugar, pepper, and Sriracha. Set aside.

2. Marinate the Beef:

In another bowl, combine beef, baking soda, garlic powder, and 1½ tablespoons of the sauce. Mix well and let marinate for 15-20 minutes.

3. Cook the Beef:

Heat 1 tablespoon oil in a wok or large skillet over high heat. Add the beef and cook for 1-2 minutes, until seared but still slightly pink. Transfer to a plate and set aside. Clean the wok/skillet.

4. Sauté the Vegetables:

In the same wok or skillet, heat another 1 tablespoon oil over high heat. Add the onion and Chinese broccoli with a pinch of salt. Sauté for 1-2 minutes, until the onion starts to char and the broccoli turns bright green.

5. Cook the Noodles:

Add another 1 tablespoon oil to the wok, followed by the rice noodles and half of the sauce. Gently toss the noodles until they soften, about 1-2 minutes.

6. Finish the Dish:

Add the bean sprouts, dark green onion segments, and the remaining sauce. Stir everything together for another 1-2 minutes, until everything is tender and well-cooked.

7. Combine and Serve:

Stir in the cooked beef and turn off the heat. Let the residual heat warm the beef. Taste and adjust seasoning if necessary. Garnish with the green onion slices. Serve hot.